Incandescent electric lamp and method of making the same



INCANDESCENT ELECTRIC LAMP AND METHOD OF MAKING THE SAME Dec, 19, 1944. G. c. SINGER Filed Oct. 14, 1942 Patented Dec. 19, 1944 'INCANDESCENT ELECTRIC LAMP AND METHOD or MAKING THE SAME Grover 0. Singer, Brownsville, Tex. Application October 14, 1942, Serial No. 461,978

3 Claims.

This invention relates to incandescent electric lamps and method of making the same.

An object of the invention is the provision of a lamphaving the base portion and globe formed integrally of glass or other transparent materials in which the inner end of the base is curved and forms the bottom of the globe with the curved portion and a section of the inner wall ofthe globe being coated with a reflecting surface.

Another object of the invention is the provi- Fig. 2 is a transverse section taken along the line 2-2 of Fig. 1.

Fig. 3 is a side view partly in section of the lamp before the reflection has been applied.

Fig. 4 is an end view of the complete lamp. Referring more particularly to the drawing, I designates a base portion which is formed of glass ,or any suitable transparent material, and this sion of a method of forming a reflector on the to the inner end of the base portion, said globe and base portion being formed integrally of glass or other transparent materials, an important step in the method being the application of a soluble substance to the wires supplying current to the usual filament so that when the reflector. has been formed the substance may be dissolved and removed whereby the wires will be free of the metal oi the reflector and a short circuit will be prevented.

A still further object of the invention is the provision of a method of forming a reflector on that inner surface of the lamp which is common to the inner ends of the glass globe and glass base portion of integral formation; the wires carrying the usual filament being protected against short circuiting through the reflector by a prior application of beeswax or molasses which is later removed by a solventaa portionof the inner surface of the globe, when desired, being frosted for increasing the adherence of the reflector to the globe, the unfrosted areas being treated with liquid wax prior to the etching steps.

This invention will be best understood from a consideration of the following detailed description, in view of the accompanying drawing forming a part of the specification; nevertheless,

Fig. 1 is avertical section of a lamp construct- I base member is formed integrally with'a bulb I I, also formed of glass.

Wires l2and I3 are embedded in the glass base portion Ill and project into the interior of the bulb II, as shown at M and IE, to which are attached the ends of a filament l6 adapted to be maintained incandescent when illumination is desired, The outer end of wire I2 is secured to a metal contact l'l, while the outer end of wire l3 projects through the base portion and is connected to a metal sleeve l8 having laterally projecting lugs or screw threads IQ for connecting the lamp in a socket of well known construction.

The inner end of the base portion III as shown at 20 is curved concavely, and this concave sur face ,continues uniformly into the curved inner side walls 2i oi the globe ll. Thus it will be seen that the curved surface 20 forms not only the inner end of the base portion H) but also the ininto strips 24 outwardly towards a closure 25 forming the top or front of the bulb. The width of the strips 24 will depend upon the extent to which it is desired to cut ofi the lateral rays of the bulb. The particular purpose of the reflecting strips 24 is to eliminate the lateral rays which are caused by the usual reflector in a headlight of an automobile and which have a tendency to blind the operator of an approaching automobile. Not only are the light rays blacked out where the strips 24 are located, but the reflector surface tends to project these rays forwardly and thus aid in illuminating the road bed in front of the driver of the vehicle. Reflecting strips 24 are formed by allowing the reflecting material to enter the passage 30 in the base member, ID, and permitting the material to flow outwardly, after which the bulb is rolled to cause the material to spread late'rally until the strip is formed.

The strip also may be formed by running melted wax through a small instrument which is inserted through the passage 30 and the instrument is so moved that the wax will clearlyoutline' the edges be applied to the space 24 until the space is completely covered. The wax can then be dissolved,

the bulb has been completely manufactured, air

is exhausted through the passage 30 and a plug 32 is sealed at the outer end, after which the metal member I! is applied to the outer end of the base portion ill.

The lamp is constructed in any well known manner without the reflector 22 so that the wires l2 and I2 will be in position and the passage 30 will be open at both ends. The lamp is now ready for the application of the reflector.

In carrying out my method for supplying a re-- flector 22 to the inner walls of the bulb H, and to the concave surface 20, either liquid beeswax or molasses is forced through the passage 30, and the bulb is moved so that this wax will cover the inner projecting portions I4 and 15 of the respective wires l2 and I3 as shown at 33 in Fig. 3. When an etching fluid is employed for cutting the glaze on the inner walls of the bulb H and the concave surface 20, in order to provide a greater adhesive surface for the materials forming the reflector, the inner projecting ends II and I5 oi the wires together with the filament I6 are entirely coated with the wax or molasses in order to protect the same against action by the etching fluid. Furthermore, all those portions of the inner walls of the bulb II which are not to be covered with the reflector are likewise covered with the liquid wax which is preferably beeswax in a molten state. when this happens, sumcient wax is forced through the passage 30 so that it will fall upon the inner face of the member 25 and the walls of the bulb are maintained ate temperature that the wax will remain fluid so that when the bulb is rotated all those portions of the inner walls of the bulb which will not be covered by the reflecting surface are given a coating of wax. After the wax coating has been properly applied, the etch- .ing materials are injected through the passage 30 and allowed to remain in the bulb for contact with the uncoated portion of the glass walls until be removed and leave the reflector 22 in the position shown in Fig. 1.

0n the other hand, where the reflecting strips 24 are desired, care must be exercised in applying these to the inner walls of the bulb that such portion will remain uncovered so that the etching fluid may attack the surface of the glass.

they have been suficiently etched for the pur- As has been stated above, when it is necessary to cut the glaze on a portion of the inside walls of the globe and the concave surface 20 in order to cause the materials forming the reflector 22 to adhere more firmly to said walls, melted beeswax is forced through the longitudinal passage 30 and the globe is rotated until that portion of t e 3 of the space 24. The reflecting material then may walls of the globe which is not provided with a mirror has been thoroughly coated with the wax. The inner ends M and I5 of the respective wires l2 and 13 are coated with wax.

After the wax coating has been completed, an etching composition which does not attack the wax, is then injected through the passage.

The composiiton, which is a solution, contains the following ingredientsby volume. 10 parts of ammonium fluoride, 18 parts of hot water, 20

parts of molasses, and 12 parts 60% hydrofluoric acid.

The ingredients are thoroughly mixed before injection. The composition is allowed to remain in contact with the exposed surfaces of the glass walls for approximately one minute, after which it is washed out by water. The wax is removed by any suitable solvent, such as, ether, chloroform or oils.

The molasses is an aid in causing the composition to adhere to the uncoated surfaces of the glass walls.

After the bulb has been thoroughly cleaned of the composition, the reflector is then applied after which the excess materials of the reflector and the wax are then removed;

The air is'exhausted and the outer end of the passage is closed by the plug 32 of cellulose acetate or other suitable cement. I

I .claim:

1. The method of forming a reflector on a portion of the inner wall of a globe of an electric lamp which has a glass base portion formed integrally with the globe, the inner end of the base and globe having a common curved surface, the base portion being provided with a longitudinal passage opening through the common surface and filament-supporting wires projecting into the globe from said curved surface which comprises the steps of forcing through the passage a soluble adhesive substance selected from the group, consisting of beeswax and molasses, turning the globe until the material coats the projecting wires and a small portion of the curved surface where each wire projects therefrom, injection through the passage materials to form the reflectors, rotating the globe to cause the last-mentioned material to coat the curved surface and the adhesive materials attached to the wires and curved surface, dissolving the adhesive material, and removing the dissolved adhesive material from the globe together with excess reflecting material.

' 2. The method of forming a reflector on a portion of the inner wall of a globe of an electric lamp which has a glass base portion formed integrally with the globe, the inner end of the base and globe having a common curved surface, the base portion being provided with a longitudinal passage opening through the common surface and filament-supporting wires projecting into the globe from said curved suriace'which comprises the steps of forcing through the passage a soluble adhesive substance selected from the group, consisting of beeswax and molasses, turning the lobe until the material coats the projecting wires and a small portion of the curved surface where each wire projects therefrom, injecting through the passage silver nitrate to form the reflectors, rotating the globe to cause the silver nitrate to coat the curved surface and the adhesive mate- 3. A method of forming a reflector on the curved bottom of a globe of an electric lamp in which wires extend from the base portion of the lamp into the globe with the base portion having a passage through which instruments are adapted to be inserted, and which comprise applying a liquid wax to the extended wires in the globe and to a. portion of the space on the curved bottom which surrounds the wires, so that after the reflector has been iormed on the curvin 10 nitrate, and applying the same to the curved bottom of the globe and to the wax enclosing the wires, dissolving the wax coating and removing the same from the globe,

GROVER c. SINGER. 

